ZoneWise | Home Energy Improvements — Cost & Payback Compared

ZoneWise case-study figures are verified. The £965/yr annual saving and ~40% gas kWh reduction are drawn from the home’s gas statements since 2019 (16,207 kWh × 5.95p: 2025 against 2020, the last full year before installation). We quote a typical reduction of ~30%; the case-study home achieved more. All other figures are sourced from Energy Saving Trust, BEAMA, and UK installer market data 2025–26.

ZoneWise payback (case study)

~2–3.5 yrs

Case-study home (verified billing data). At the typical ~30% saving on a similar-sized home: ~3–5 yrs. Loft and cavity insulation can pay back as fast.

Solar PV

6–12 yrs

Comparable annual saving but several times longer to recover cost. Scotland yield is lower than the UK average.

Heat pump (ASHP)

7–18 yrs

Lower annual saving vs gas boiler, high install disruption, poor fit for solid-wall Victorian homes.

Solution	Installed Cost	Annual Saving	Simple Payback	Disruption	Victorian Home Suitability	Verdict
Smart Heating Controls
ZoneWise Multi-Zone System Drayton Wiser • professional install & optimisation Verified outcome	£1,995–£3,495 No grants available	£965/yr Case study home (~40%, verified billing data). Typical reduction ~30%	~2.0–3.5 yrs Case study. ~3–5 yrs at typical ~30% Very fast	Minimal — 1–2 days, no structural work	Ideal — works with existing radiators & boiler	Strong payback
Smart Thermostat Only Hive / Nest / tado° • single zone	£150–£350 incl. installation	£75–£200/yr 8–16% gas reduction	12–24 months Very fast	Minimal — hours	Fully suitable	Good starter
Insulation
Loft Insulation Mineral wool, from scratch ECO4 may apply	£300–£1,200 Free if ECO4 eligible	£150–£350/yr	2–4 yrs Fast	Low — 1 day	Suitable if loft present	High value
Cavity Wall Insulation Injected beads / mineral wool Not for Victorian homes	£600–£1,500	£200–£400/yr	3–6 yrs Good	Moderate — drilling	⚠ Solid walls — cavity insulation not applicable to Victorian homes	Inapplicable
Solid Wall Insulation External or internal boarding	£8,000–£22,000 External typically £12k–£17k	£400–£600/yr	20–40 yrs Very long	Major — weeks of work	⚠ Applicable but planning & conservation implications	Poor ROI
Renewables & Boiler Replacement
Solar PV Panels 4–6 kW system, no battery 0% VAT to Mar 2027	£5,700–£12,000 +£3k–£5k for battery	£500–£900/yr incl. SEG export payments	6–12 yrs Moderate	Moderate — scaffolding	⚠ Roof aspect key; Scotland yield lower than England average	Good long-term
Solar PV + Battery Storage 4–6 kW system + 4–5 kWh battery 0% VAT to Mar 2027	£9,000–£18,000	£700–£1,100/yr	11–16 yrs Long	Significant	⚠ Scotland payback ~1–2 yrs longer than England	Long payback
Air Source Heat Pump Replacing gas boiler £7,500 BUS grant available	£7,000–£14,000 Net £500–£6,500 after grant	£250–£400/yr vs modern gas boiler	7–18 yrs Long	Major — radiator upgrades likely, external unit required	⚠ Problematic — solid walls lose heat faster; oversized radiators often required in older homes	Weak case here
Ground Source Heat Pump Borehole or ground loop £7,500 BUS grant available	£12,500–£20,000 Net after grant	£400–£600/yr vs modern gas boiler	16–30 yrs Very long	Extensive — garden excavation or borehole	⚠ Garden access required; same wall-loss problem as ASHP	Very poor ROI
New Condensing Gas Boiler Replacing old boiler only	£2,000–£4,500	£100–£350/yr vs old G-rated boiler	8–20 yrs Moderate–long	Moderate — 1–2 days	Suitable but gains low with a modern boiler already in place	Marginal
Double / Triple Glazing Full house replacement	£4,000–£12,000 Planning issues for Victorian fronts	£50–£110/yr Heating contribution only	40–80 yrs Extremely long	Significant	⚠ Listed building & conservation area restrictions common	Very poor ROI

† Heat pump payback shown after £7,500 BUS grant; without grant, payback extends to 25–40 yrs at typical gas-boiler savings. † Solar payback in Scotland is ~1–2 years longer than the UK average due to lower irradiance. † Disruption scale: 1 dot = hours / minimal; 5 dots = weeks / major structural work. † ZoneWise case-study saving (£965/yr) = 16,207 kWh × 5.95p (2025 against 2020; system installed late 2021); verified from the home’s gas statements. † Sources: Energy Saving Trust, BEAMA / Salford University 2021, Drayton Wiser published data, FMB, Carbon Brief, Ofgem Q1 2026.

Home Energy ImprovementsCost & Payback Compared

Home Energy Improvements
Cost & Payback Compared